1. Technical Field of the Invention
The present invention relates to solar concentrators and solar collector systems. More particularly, the present invention relates to a linear solar concentrator which utilizes a portion of a parabolic arc for a first reflection surface and a planar secondary reflection surface for concentrating solar energy in a substantially linear fashion on a predetermined portion of the first reflection surface.
2. Description of Related Art
Solar concentrators work by collecting sunlight from a large area and concentrating sunlight into a smaller area. There are identifiable techniques for converting solar energy into useable forms, but whether or not the solar energy is collected and converted on a substantial scale is controlled by economics. If the cost of installing and maintaining a solar energy collection system is lower than the alternatives, then widespread use of the solar energy collection system is possible. The bulk of the cost for solar energy collection systems is in the initial investment. Thus, solar systems must begin to pay for themselves when the system is utilized.
Presently, there exist large linear solar concentrators. FIG. 1 depicts an exemplary prior art linear concentrator. The depicted concentrator was the result of the EUCLIDES project which was subsidized by the European Union. Dual parabolic trough portions cast a beam irradiance onto a strip of solar cells positioned linearly along the Dual parabolic trough portion's focal line. Drawbacks of this prior art type of linear concentrator relate to the size and shape of the concentrator as well as the position of the focal line. The geometry of such concentrators requires that the linear trough must "stick-up" high above the ground in order to focus the solar energy to the focal lines of the trough. The parabolic surfaces become a large "sail" and require substantial support due to subjection to the strength of strong winds. The singular parabolic shape of the concentrator is not easily reinforceable and is easily twisted or flexed out of its required parabolic shape such that the reflected solar energy misses the prescribed linear conglomerate of solar cells.
Furthermore, the focal line positioning of the solar collectors requires its own separate supporting structure such that the solar collectors are held on the focal line associated with each parabolic solar concentrator.
Cooling of the solar collectors is a difficult task due to the movement of the focal line as the linear parabolic trough tracks the sun. The focal line will move along a defined arc as the depicted linear parabolic trough collector pivots on a line parallel with the focal line. Such a situation requires flexible plumbing pieces that connect to the solar collection area. The flexible plumbing carries coolant, such as water, to cool the solar collector devices while the solar energy is being concentrated on them. Flexible plumbing tends to crack, degrade and leak when it is used in outdoor conditions. Thus, one of the major repair costs for prior art solar concentrator/collection systems is the repair and maintenance of the associated flexible plumbing for cooling the collector area of the solar concentrator.
What is needed is a solar concentrator configuration that has a relatively low manufacturing cost, that is structurally more rigid than a simple linear parabolic trough, that pivots substantially at the focal line of the linear concentrator to effectively eliminate a substantial need for flexible cooling plumbing, and that maintains a profile close to the ground such that the solar concentrator structure is less likely to sustain damage due to high winds.